IN VEGETABLE BIOLOQT. G03 



accompanying two of his figures, speaks of cells " anastomosing " 

 and " uniting to form a network." At the same time it must be 

 remembered that continuity is only casually figured in the great 

 illustrated works on Phycology, and has often been overlooked 

 even by observers of the first order *. Indeed, it is not until we 

 come down to recent times that we find the subject to have been 

 specially attended to. 



Mr. Archer t seems to have broken the first ground by his 

 study of Ballia callitricha and allied species, the young cells of 

 which he concluded to be in open communication by means of a 

 pore, which is immediately sealed up by the development, at both 

 its ends, of a plug or " stopper " formed of a substance giving 

 none of the reactions of starch or cellulose. Professor Wright X, 

 of Dublin, observed similar phenomena in Polysiphonia and 

 Oriffiihsia setacea. A propos of the growth of Polysiphonia, he 

 says (p. 516) : — " In its early condition the tips of the rays and of 

 the two ends are quite distinctly open, and the protoplasmic con- 

 tents freely communicate with the tube-like cells above and 

 below and the siphon-cells around it ; but as it becomes mature, 

 and as a cell-wall is definitely formed around it, these pore- 

 openings are closed up, and these plugs will prevent sometimes 

 even the ' stopper '-like form described by Archer ; so that here, 

 as in Griffithsia, it seems to me that these plugs or stoppers are, 

 as it were, only the result of the cell finally closing itself up." 

 Merely mentioning that Agardh § figures some cases of undoubted 

 continuity, we come to the poorly illustrated memoir of Schmitz ||, 

 whose views are quite different from those of his predecessors* 

 He holds that, with the exception of the Corallines, whose cells 

 intercommunicate by wide open pits, the pits are closed by means 

 of an exceedingly thin membrane, on each side of which lies a 

 plate of very thick substance, dyed intensely with hematoxylin 

 &c. These plates, he says, are connected together by means of 

 numerous strands of protoplasm, which penetrate the closing 

 membrane chiefly or exclusively at its circumference, and unite 

 laterally to form a hollow cylindrical band of intercellular com- 



* For example, Pringsheim, in his "Beitr. z. Morph. d. Meeres Algen," Abhandl. 

 d. Kbnigl. Acad. d. Wissensch. z. Berlin, 1862. 

 t Trans. Linn. Soc, new series, Botany, vol. i. 

 t Trans. Koy. Irish Acad. vol. xxvi. 1879. 

 § ' Florideernes Morphologi.' 

 I! Sitzb. d. Konigl. Acad. d. Wissensch. z. Berlin, 1883. 



